1. Field of the Invention
The present invention provides a testing circuit and a related testing method, and more particularly, to a testing circuit for injecting a time jitter for testing a capability to receive signals and a related testing method.
2. Description of the Prior Art
All electronic devices must be tested during fabrication. A test for testing the capability to receive signals is performed on electronic devices to determine whether the received signals are precisely acknowledged. An under-test electronic device of the prior art comprises a core circuit and a testing circuit. An output signal generated by the core circuit is transmitted to a testing instrument through an output of the core circuit. The testing instrument receives and processes the output signal of the core circuit for generating a testing signal. The testing signal is transmitted to an input of the core circuit. The capability to receive signals of the under-test electronic device is confirmed by confirming whether the output signal outputted from the output of the core circuit matches the testing signal received at the input of the core circuit.
Please refer to FIG. 1. FIG. 1 is a diagram of a high-speed testing instrument 120 of the prior art testing an under-test electronic device 110. The under-test electronic device 110 comprises an output 112 and an input 114. The output 112 is coupled to an input 124 of the high-speed testing instrument 120. The input 114 is coupled to an output 122 of the high-speed testing instrument 120. A processing circuit 126 of the high-speed testing instrument 120 is utilized for processing the signals received at the input 124. The high-speed testing instrument 120 generates a testing signal according to requirements and outputs the testing signal at the output 122 to the input 114 of the under-test electronic device 110 for testing the capability to receive signals.
Along with the growth of processing speed of electronic devices, the requirement for high-speed testing is also growing. “High-speed” means that the processing speed of the processing circuit 126 is faster or equal to the processing speed of the under-test electronic device 110. The built-in processing circuit 126, which is capable of processing signals efficiently, of the high-speed testing instrument 120 dynamically analyzes the electrical properties of the output signals of the under-test electronic device 110 and generates a testing signal to the input 114 of the under-test electronic device 110 according to various testing conditions. However, the fabricating cost required for the high-speed testing instrument 120 make is unaffordable. Besides, although additional high-speed testing equipment can be used as a testing instrument to help complete a test by injecting a time jitter, the fabricating cost of the additional high-speed testing equipment is also unaffordable.